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Full text of "The Cambridge Natural History"

BLOWHOLE AND SPOUTING

345

Is*  sj-en on  the throat.     This is especially the cap*? with the

'c   \Vliui< ,  Jtl*'grrj>trrft, is

in   which   group  the
to   be   inzludetl.     The   whales   of

these two geitf:f'i "/yV/^oi/^y/ov/
an* i Sfegaptrra) have >t large num-
ber of the throat furrows — as
many as sixty have been counted.
Some other Whales have n smaller
number ; thus IZharhiwMctes has
but two on each side, ant! the
I'hyseteridae have not many more.
These furrows are absent in very
young embryos. It is thought
by Professor Kitten thai that they
allow of a wide opening of the

The blow-hole of Whales is, of

course, tlift aperture of the nostrils,
which ure not  so far back  in  the

foetus   as  in   the   adult.    By   the

characters    of    the    nostrils    the

Toothed   Whales   can   be   distin-

guished from the Baleen Whales ;

in the latter the orifice is double,

in the former single.    In embryos

of Dolphins, however, the two aper-

tures axe quite  independent.    The

phenomena of spouting have often

been misinterpreted.1     When the

Whale   breathes, the  expired   air

rushes  out   through  the  nostrils.

The  water  vapour   in  the breath

condenses into  drops of water in

the    cold   Arctic   regions   where

the phenomenon has been mainly

observed.     Hence the idea that water taken in  at the mouth is

expelled through the blow-hole.     As the Whale approaches the

surface to breathe, it may be that some of the water of the        is

1 *s And at hi* gilltf draws in, and at his trunk ftpouti out, a se%*' wrote Milton,
and think many others.

Fro. 181.—-Dorsal surface of bo»es of
right anterior limb of Round-headed
Etolphiu (Ottibicephalustnelas), x -j\.
The shaded portions of the digits
axe cartilaginous. cf Cuneiform ; If*
lh.ran.erus j L, lunar ; JL, radius ; *,
scaphoid ; td, trapezoid or magnum ;
U, wlna ; «»tiuciforro ; I/- V, digits,
(From Flower's